Phase Transition Behavior of Block Copolymer Thin Films and Thickness Dependence

Understanding on the phase behaviors and transitions of Block copolymers (BCPs) such as order-to-disorder and order-to-order transitions plays a crucial role in designing a long-range order structure of self-assembled arrays. In this study, we investigated phase transition behavior of (BCPs) in film geometry, and compared with that of bulk system. When the BCP is confined in a film geometry, the interfacial interactions at air/polymer and polymer/substrates influence the phase transition temperatures of BCP and their effects on BCP films were more significant in thinner films. The morphologies and transition temperatures of BCP films were investigated by Grazing Incidence Small-Angle X-ray Scattering (GISAXS) measurements and Transmission Electron Microscopy (TEM).